Hacker Newsnew | past | comments | ask | show | jobs | submitlogin
Process for mass producing Japanese 500 yen coins (theawesomer.com)
71 points by geox on Nov 27, 2023 | hide | past | favorite | 35 comments


Ah ha now we're speaking my language! :)

Fun fact: "Mint" condition coins actually are measured on a 10-point scale (from 60 to 70...because...reasons...as part of a broader 70-point scale also because reasons).

In the video, note how the finished coins are unceremoniously ejected into a big bin straight after striking. During that process, many of the coins get little nicks and bumps and scratches. This has been the way for hundreds of years.

Because of this, most of the mass-production coins out there are far from perfect. So even among a group of coins literally hot off the presses, truly perfect ones (graded 70) are super hard to find. In the world of vintage coins (non-modern era - generally pre-1900), perfect 70s simply don't exist, and 69s go for $hundreds of thousands (or $millions).

This is different for modern coins, particularly for issues where the mints are marketing them specifically for collectors. 70s are easy to find. But for the true workhorse mass-market coins, perfection is not the norm.


> But for the true workhorse mass-market coins, perfection is not the norm.

Yup, I was very disappointed with the video in TFA.

Here's a proper factory minting a proper coin:

https://youtu.be/sM4lyJdCO_E


can that really be counted as a coin anymore... it's just a 10kg cylinder with a nice pattern


Coins don’t need to be tiny and round, just small, standardized mediums of exchange. There’s plenty of square coins: https://en.wikipedia.org/wiki/Coin#/media/File:Coin_of_the_B...

Larger denominations of precious metal backed currency like gold bricks can be considered coins, it’s rather arbitrary as to when something is to large to be considered a coin.


Ancient Chinese quasi-functional spade and knife coins are an even more interesting departure from tiny round discs than square or oblong coins.


> Fun fact: "Mint" condition coins actually are measured on a 10-point scale (from 60 to 70...because...reasons...as part of a broader 70-point scale also because reasons).

Don't forget the + grades (MS64+ etc) - 19 different types of mint condition!


Australian Mint is in canberra. Hi tech machines, but low(ish) tech site security. You do the obvious things. Scanners. Background checks.

I did a tour, they mentioned how a bunch of the low end labour used to wear "ugg" boots which are ankle boots made of sheepskins, wool-side inside. They made great stow-away for a few $2 coins from time to time, no clinking because of the wool. But if you got too greedy the boots started to sag...

I suspect it's apocryphal. Ugg boots sag anyways.

To the high-tech machines: the CSIRO (national science and technology research and tech commercialisation body) did work on high energy beam deposits, to make the die surfaces last longer. They were on the brink of exploring holographic coin prints when I went round, having just done bimetallic inserts and colour. At the rate of stamping, you loose the fine detail on the queen's face very quickly. The trial of the pyx is about this kind of qualitative judgement: Is this coin manufacture good enough to be kept as a mint?

At least one escape caper film (French?) has them use the aluminium coins as welding rod, making a digging tool to get out of the cell (using 200v sparks from bare wires to weld bits of metal together) -francs outre-mer I saw in Noumea were aluminium, featherweight coins.

The 1 yen coin is so light it will float on water.

The jokes about the cost of making a coin exceeding its face value (Pratchett) have some validity. Coins are solid expressions of value but their utility is their movement more than their actual denomination. Hence currency..


Interesting - any source on the CSIRO helping with the bimetallic inserts and colour?


No, only the epitaxial growth to harden the dies:

https://www.csiro.au/en/research/production/materials/thin-f...

Maybe they used other collaborations for the other stuff.


Sounds like a lot of work to steal like, what, $10 max?


The smart ones manufacture error coins that sell for thousands of dollars - there were many made in the 1970s that combined Australian/New Zealand/Fijian obverses and reverses. Through the 2010s there has been another surge of such manufactured errors - generally one dollar coins made with 10c portraits (the 10c portrait is slightly smaller so it's a noticeable mistake).


I think the target was special limited-edition runs of coins which have above-denomination value. But yes, a lot of theft seems pointless.

A case in Brisbane involved a parking-meter attendant who had a gambling habit and sifted coins out of the street meters to put into slots. hundreds and thousands of them, over a career. If you steal below some threshold, the back end smarts (pre-digital) didn't "see" the discrepancy between meter state, and cash inputs. Probably some smart stats showed the anomoly, and then time series analysis showed when it cropped up.

All to pull a lever.


> All to pull a lever.

A lot of people worked really hard to make that lever feel really, really attractive to pull.


Of potential interest, the source YouTube channel is prolific and covers many Japanese manufacturing processes: https://youtube.com/@processx


I've been watching all their videos. It's basically a modern 'how it's made' set in japan.


I much prefer the videos without any music at all


This video came up in my yt feed a couple of days ago. I watched the rice cooker video that was also hn front page a few weeks back. And now The Algorithm thinks I like Japanese undustrial manufacturing videos. I'm not complaining.

The thing that confused me though: why punch out the middle, only to put it back in again? It doesn't look like they're made from dissimilar metals like Euros?


That is made from three dissimilar metals.

https://www.mof.go.jp/policy/currency/bill/20210816.html



Asianometry on Toyota run plant from GM. https://youtu.be/ZjxZ2Eh9GrA


500 yen coins really do have a weight to them, they feel valuable and can almost buy you a proper lunch. It's a shame most vending machines and subway ticket dispensers only accept the old 500 yen coin though.


Nice. Japan's mint does its own hot metal work, rolling mill and all. The US Denver mint does not; the metal coils come from some commercial rolling mill. There are no precious metals involved any more, after all.


Australia' mint outsources it all - seemingly it's cheaper to import the blanks from South Korea than to do it locally.


I traveled to Japan last Summer and noticed many vending machines had problems with the new bimetallic 500-yen coin.

Must be a huge headache upgrading all those machines. But then I can understand you'd want to keep the 500-yen coin hard to counterfeit since it's quite high-denomination.


It is not just vending machines. I have had the new 500-yen coins rejected on buses, in food stores, etc. It will happen gradually, but I think it is the first time in my 15 years of experiencing Japan that there has been any change to a coin so I expect it to take at least another year.


There’s also upcoming changes to paper bills too, vending machine operators might be waiting to do both at the same time.


I am envision them still running a 1999 VB6 app ported in 1999 from an old DOS Fortran EXE to calculate the exact kilos of pure metals to compensate for alloy composition differences as they melt the scrap crucible to keep the alloy in spec.



That page is seriously 90% ads… I don’t think I’ve ever seen a ratio like this before.


It will only get worse. Install uBlock Origin today.


Cute coin mascots at 8:40 mark https://youtu.be/WiRoSZqg1EE?t=520


Man, 60fps and the shaky hand while panning/zooming (and it's a lot of those things) make this a motion-sickness-inducing video.

But slowing it to 0.75x seems to work.


I carry one of these things. I sometimes use it for shopping cards that normally take Canadian loonies ($1 coins).


Cashiers here switch carts at checkout. Customer gets the last customers' cart.


[video]




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: